.\" Copyright (c) 2005 Gleb Smirnoff
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.Dd March 2, 2010
.Dt NG_IPFW 4
.Os
.Sh NAME
.Nm ng_ipfw
.Nd interface between netgraph and IP firewall
.Sh SYNOPSIS
.In netinet/ip_var.h
.In netgraph/ng_ipfw.h
.Sh DESCRIPTION
The
.Nm ipfw
node implements interface between
.Xr ipfw 4
and
.Xr netgraph 4
subsystems.
.Sh HOOKS
The
.Nm ipfw
node supports an arbitrary number of hooks,
which must be named using only numeric characters.
.Sh OPERATION
Once the
.Nm
module is loaded into the kernel, a single node named
.Va ipfw
is automatically created.
No more
.Nm ipfw
nodes can be created.
Once destroyed, the only way to recreate the node is to reload the
.Nm
module.
.Pp
Packets can be injected into
.Xr netgraph 4
using either the
.Cm netgraph
or
.Cm ngtee
commands of the
.Xr ipfw 8
utility.
These commands require a numeric cookie to be supplied as an argument.
Packets are sent out of the hook whose name equals the cookie value.
If no hook matches, packets are discarded.
Packets injected via the
.Cm netgraph
command are tagged with
.Vt "struct ipfw_rule_ref" .
This tag contains information that helps the packet to re-enter
.Xr ipfw 4
processing, should the packet come back from
.Xr netgraph 4
to
.Xr ipfw 4 .
.Pp
Packets received by a node from
.Xr netgraph 4
subsystem must be tagged with
.Vt "struct ipfw_rule_ref"
tag.
Packets re-enter IP firewall processing at the next rule.
If no tag is supplied, packets are discarded.
.Sh CONTROL MESSAGES
This node type supports only the generic control messages.
.Sh SHUTDOWN
This node shuts down upon receipt of a
.Dv NGM_SHUTDOWN
control message.
Do not do this, since the new
.Nm ipfw
node can only be created by reloading the
.Nm
module.
.Sh SEE ALSO
.Xr ipfw 4 ,
.Xr netgraph 4 ,
.Xr ipfw 8 ,
.Xr mbuf_tags 9
.Sh HISTORY
The
.Nm ipfw
node type was implemented in
.Fx 6.0 .
.Sh AUTHORS
The
.Nm ipfw
node was written by
.An Gleb Smirnoff Aq Mt glebius@FreeBSD.org .
